The present invention relates to a mechanism that automatically opens the breech block wedge on a semiautomatic weapon, especially a tank cannon with a training liner.
When tank cannons are fired for practice and training, they are often equipped with training liners to make it possible to employ smaller-caliber and hence more cost-effective ammunition.
This ammunition, with calibers of up to 35 mm, does not, however, create enough recoil for the breech block wedge to open automatically to receive the next round. The loader must open the wedge by hand after every round by rotating the opener shaft with a manual lever. This is very difficult and takes a relatively long time, especially in the field. It is not even approximately comparable in time and function to loading and firing with ammunition of the caliber (120 mm, for example) that is conventional for this weapon, wherein breech will open automatically as a result of recoil, allowing a firing rate of up to 8 rounds a minute.
To meet such a requirement with some degree of approximation, it is necessary for the breech block wedge to open automatically, independently of the loader, and in a specific sequence when a training liner is employed with small-caliber ammunition.
It is impossible to simulate recoil in order to trigger normal automatic breech block-wedge opening without considerable engineering expense because of the power that would be required.